ESR1 and breast cancer: In addition, compared to the non-Sjögren cohort, the Sjögren cohort had a higher risk of estrogen receptor positivity in breast cancer (HR: 1.222, 95% CI: 0.782–1.907) but a lower risk of progesterone receptor positivity (HR: 0.531, 95% CI: 0.048–5.861), although neither reached statistical significance.